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Antimitochondrial M2 Antibody, Serum — Qualitative, Immunofluorescence Assay

Published: August 9, 2026Updated: August 16, 2026

Detects antimitochondrial M2 antibodies in serum, most commonly used to help evaluate suspected primary biliary cholangitis.

Quick summary

["A positive result supports primary biliary cholangitis, but it must be interpreted with liver tests and other findings."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
93868-8
Short code
AMPAR2 Ab Ser Ql CBA IFA
Synonyms
AMPAR2 Ab Ser Ql CBA IFA
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cba-ifa
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This blood test looks for antimitochondrial M2 antibodies, also called AMA-M2. These antibodies target a protein inside mitochondria, which are small structures that produce energy for cells.

Why might I need this test?

The test is often ordered when liver tests suggest cholestasis or when primary biliary cholangitis, an autoimmune liver disease, is suspected. It may also be used alongside other autoimmune tests.

How is the test performed?

Blood is drawn from a vein and the serum is separated. The laboratory then checks the serum for AMA-M2 antibodies, usually with an immunofluorescence-based method, and reports whether they are detected.

How do I prepare for the test?

Fasting is usually not required for this test. Follow any specific instructions from your healthcare professional and tell the laboratory if you have an autoimmune condition, liver disease, or are pregnant.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A positive AMA-M2 result strongly supports primary biliary cholangitis, particularly when it is accompanied by an elevated alkaline phosphatase level. However, the antibody may occasionally be present in other autoimmune diseases or in healthy people, so the result must be interpreted with liver tests and other clinical findings. A negative result does not completely exclude primary biliary cholangitis.

Short name

AM-M2 antibody

Frequently asked questions

Does a positive AMA-M2 result mean I definitely have primary biliary cholangitis?
No. A positive result is strongly associated with the disease, but your clinician must consider symptoms, liver test results, and other findings before making a diagnosis.
What other tests are commonly used with AMA-M2?
Clinicians often review liver tests, especially alkaline phosphatase and bilirubin, along with symptoms and other autoimmune blood tests.
Can I take medications before this test?
Most medicines do not require you to stop them before an AMA-M2 test. If you are on corticosteroids or other immune treatments, discuss the test with your healthcare professional because treatment can affect antibody results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy